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Commit 38de03d2 authored by Arend van Spriel's avatar Arend van Spriel Committed by Johannes Berg
Browse files

nl80211: add feature for BSS selection support 



Introducing a new feature that the driver can use to
indicate the driver/firmware supports configuration of BSS
selection criteria upon CONNECT command. This can be useful
when multiple BSS-es are found belonging to the same ESS,
ie. Infra-BSS with same SSID. The criteria can then be used to
offload selection of a preferred BSS.

Reviewed-by: default avatarHante Meuleman <meuleman@broadcom.com>
Reviewed-by: default avatarFranky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: default avatarPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: default avatarLei Zhang <leizh@broadcom.com>
Signed-off-by: default avatarArend van Spriel <arend@broadcom.com>
[move wiphy support check into parse_bss_select()]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent f59374eb

include/net/cfg80211.h

+34 −0
Original line number Diff line number Diff line
@@ -1858,6 +1858,33 @@ struct cfg80211_ibss_params { 
	struct ieee80211_ht_cap ht_capa_mask;

};



/**

 * struct cfg80211_bss_select_adjust - BSS selection with RSSI adjustment.

 *

 * @band: band of BSS which should match for RSSI level adjustment.

 * @delta: value of RSSI level adjustment.

 */

struct cfg80211_bss_select_adjust {

	enum ieee80211_band band;

	s8 delta;

};



/**

 * struct cfg80211_bss_selection - connection parameters for BSS selection.

 *

 * @behaviour: requested BSS selection behaviour.

 * @param: parameters for requestion behaviour.

 * @band_pref: preferred band for %NL80211_BSS_SELECT_ATTR_BAND_PREF.

 * @adjust: parameters for %NL80211_BSS_SELECT_ATTR_RSSI_ADJUST.

 */

struct cfg80211_bss_selection {

	enum nl80211_bss_select_attr behaviour;

	union {

		enum ieee80211_band band_pref;

		struct cfg80211_bss_select_adjust adjust;

	} param;

};



/**

 * struct cfg80211_connect_params - Connection parameters

 *
@@ -1895,6 +1922,7 @@ struct cfg80211_ibss_params { 
 * @vht_capa_mask: The bits of vht_capa which are to be used.

 * @pbss: if set, connect to a PCP instead of AP. Valid for DMG

 *	networks.

 * @bss_select: criteria to be used for BSS selection.

 */

struct cfg80211_connect_params {

	struct ieee80211_channel *channel;
@@ -1918,6 +1946,7 @@ struct cfg80211_connect_params { 
	struct ieee80211_vht_cap vht_capa;

	struct ieee80211_vht_cap vht_capa_mask;

	bool pbss;

	struct cfg80211_bss_selection bss_select;

};



/**
@@ -3186,6 +3215,9 @@ struct wiphy_vendor_command { 
 *	low rssi when a frame is heard on different channel, then it should set

 *	this variable to the maximal offset for which it can compensate.

 *	This value should be set in MHz.

 * @bss_select_support: bitmask indicating the BSS selection criteria supported

 *	by the driver in the .connect() callback. The bit position maps to the

 *	attribute indices defined in &enum nl80211_bss_select_attr.

 */

struct wiphy {

	/* assign these fields before you register the wiphy */
@@ -3308,6 +3340,8 @@ struct wiphy { 
	u8 max_num_csa_counters;

	u8 max_adj_channel_rssi_comp;



	u32 bss_select_support;



	char priv[0] __aligned(NETDEV_ALIGN);

};

include/uapi/linux/nl80211.h

+52 −0
Original line number Diff line number Diff line
@@ -1797,6 +1797,12 @@ enum nl80211_commands { 
 *	in a PBSS. Specified in %NL80211_CMD_CONNECT to request

 *	connecting to a PCP, and in %NL80211_CMD_START_AP to start

 *	a PCP instead of AP. Relevant for DMG networks only.

 * @NL80211_ATTR_BSS_SELECT: nested attribute for driver supporting the

 *	BSS selection feature. When used with %NL80211_CMD_GET_WIPHY it contains

 *	attributes according &enum nl80211_bss_select_attr to indicate what

 *	BSS selection behaviours are supported. When used with %NL80211_CMD_CONNECT

 *	it contains the behaviour-specific attribute containing the parameters for

 *	BSS selection to be done by driver and/or firmware.

 *

 * @NUM_NL80211_ATTR: total number of nl80211_attrs available

 * @NL80211_ATTR_MAX: highest attribute number currently defined
@@ -2174,6 +2180,8 @@ enum nl80211_attrs { 


	NL80211_ATTR_PBSS,



	NL80211_ATTR_BSS_SELECT,



	/* add attributes here, update the policy in nl80211.c */



	__NL80211_ATTR_AFTER_LAST,
@@ -4667,4 +4675,48 @@ enum nl80211_sched_scan_plan { 
		__NL80211_SCHED_SCAN_PLAN_AFTER_LAST - 1

};



/**

 * struct nl80211_bss_select_rssi_adjust - RSSI adjustment parameters.

 *

 * @band: band of BSS that must match for RSSI value adjustment.

 * @delta: value used to adjust the RSSI value of matching BSS.

 */

struct nl80211_bss_select_rssi_adjust {

	__u8 band;

	__s8 delta;

} __attribute__((packed));



/**

 * enum nl80211_bss_select_attr - attributes for bss selection.

 *

 * @__NL80211_BSS_SELECT_ATTR_INVALID: reserved.

 * @NL80211_BSS_SELECT_ATTR_RSSI: Flag indicating only RSSI-based BSS selection

 *	is requested.

 * @NL80211_BSS_SELECT_ATTR_BAND_PREF: attribute indicating BSS

 *	selection should be done such that the specified band is preferred.

 *	When there are multiple BSS-es in the preferred band, the driver

 *	shall use RSSI-based BSS selection as a second step. The value of

 *	this attribute is according to &enum nl80211_band (u32).

 * @NL80211_BSS_SELECT_ATTR_RSSI_ADJUST: When present the RSSI level for

 *	BSS-es in the specified band is to be adjusted before doing

 *	RSSI-based BSS selection. The attribute value is a packed structure

 *	value as specified by &struct nl80211_bss_select_rssi_adjust.

 * @NL80211_BSS_SELECT_ATTR_MAX: highest bss select attribute number.

 * @__NL80211_BSS_SELECT_ATTR_AFTER_LAST: internal use.

 *

 * One and only one of these attributes are found within %NL80211_ATTR_BSS_SELECT

 * for %NL80211_CMD_CONNECT. It specifies the required BSS selection behaviour

 * which the driver shall use.

 */

enum nl80211_bss_select_attr {

	__NL80211_BSS_SELECT_ATTR_INVALID,

	NL80211_BSS_SELECT_ATTR_RSSI,

	NL80211_BSS_SELECT_ATTR_BAND_PREF,

	NL80211_BSS_SELECT_ATTR_RSSI_ADJUST,



	/* keep last */

	__NL80211_BSS_SELECT_ATTR_AFTER_LAST,

	NL80211_BSS_SELECT_ATTR_MAX = __NL80211_BSS_SELECT_ATTR_AFTER_LAST - 1

};



#endif /* __LINUX_NL80211_H */

net/wireless/core.c

+7 −0
Original line number Diff line number Diff line
@@ -626,6 +626,13 @@ int wiphy_register(struct wiphy *wiphy) 
		     !rdev->ops->set_mac_acl)))

		return -EINVAL;



	/* assure only valid behaviours are flagged by driver

	 * hence subtract 2 as bit 0 is invalid.

	 */

	if (WARN_ON(wiphy->bss_select_support &&

		    (wiphy->bss_select_support & ~(BIT(__NL80211_BSS_SELECT_ATTR_AFTER_LAST) - 2))))

		return -EINVAL;



	if (wiphy->addresses)

		memcpy(wiphy->perm_addr, wiphy->addresses[0].addr, ETH_ALEN);

net/wireless/nl80211.c

+111 −0
Original line number Diff line number Diff line
@@ -402,6 +402,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { 
	[NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 },

	[NL80211_ATTR_REG_INDOOR] = { .type = NLA_FLAG },

	[NL80211_ATTR_PBSS] = { .type = NLA_FLAG },

	[NL80211_ATTR_BSS_SELECT] = { .type = NLA_NESTED },

};



/* policy for the key attributes */
@@ -486,6 +487,15 @@ nl80211_plan_policy[NL80211_SCHED_SCAN_PLAN_MAX + 1] = { 
	[NL80211_SCHED_SCAN_PLAN_ITERATIONS] = { .type = NLA_U32 },

};



static const struct nla_policy

nl80211_bss_select_policy[NL80211_BSS_SELECT_ATTR_MAX + 1] = {

	[NL80211_BSS_SELECT_ATTR_RSSI] = { .type = NLA_FLAG },

	[NL80211_BSS_SELECT_ATTR_BAND_PREF] = { .type = NLA_U32 },

	[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST] = {

		.len = sizeof(struct nl80211_bss_select_rssi_adjust)

	},

};



static int nl80211_prepare_wdev_dump(struct sk_buff *skb,

				     struct netlink_callback *cb,

				     struct cfg80211_registered_device **rdev,
@@ -1731,6 +1741,25 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev, 
			    rdev->wiphy.ext_features))

			goto nla_put_failure;



		if (rdev->wiphy.bss_select_support) {

			struct nlattr *nested;

			u32 bss_select_support = rdev->wiphy.bss_select_support;



			nested = nla_nest_start(msg, NL80211_ATTR_BSS_SELECT);

			if (!nested)

				goto nla_put_failure;



			i = 0;

			while (bss_select_support) {

				if ((bss_select_support & 1) &&

				    nla_put_flag(msg, i))

					goto nla_put_failure;

				i++;

				bss_select_support >>= 1;

			}

			nla_nest_end(msg, nested);

		}



		/* done */

		state->split_start = 0;

		break;
@@ -5758,6 +5787,73 @@ static int validate_scan_freqs(struct nlattr *freqs) 
	return n_channels;

}



static bool is_band_valid(struct wiphy *wiphy, enum ieee80211_band b)

{

	return b < IEEE80211_NUM_BANDS && wiphy->bands[b];

}



static int parse_bss_select(struct nlattr *nla, struct wiphy *wiphy,

			    struct cfg80211_bss_selection *bss_select)

{

	struct nlattr *attr[NL80211_BSS_SELECT_ATTR_MAX + 1];

	struct nlattr *nest;

	int err;

	bool found = false;

	int i;



	/* only process one nested attribute */

	nest = nla_data(nla);

	if (!nla_ok(nest, nla_len(nest)))

		return -EINVAL;



	err = nla_parse(attr, NL80211_BSS_SELECT_ATTR_MAX, nla_data(nest),

			nla_len(nest), nl80211_bss_select_policy);

	if (err)

		return err;



	/* only one attribute may be given */

	for (i = 0; i <= NL80211_BSS_SELECT_ATTR_MAX; i++) {

		if (attr[i]) {

			if (found)

				return -EINVAL;

			found = true;

		}

	}



	bss_select->behaviour = __NL80211_BSS_SELECT_ATTR_INVALID;



	if (attr[NL80211_BSS_SELECT_ATTR_RSSI])

		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_RSSI;



	if (attr[NL80211_BSS_SELECT_ATTR_BAND_PREF]) {

		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_BAND_PREF;

		bss_select->param.band_pref =

			nla_get_u32(attr[NL80211_BSS_SELECT_ATTR_BAND_PREF]);

		if (!is_band_valid(wiphy, bss_select->param.band_pref))

			return -EINVAL;

	}



	if (attr[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST]) {

		struct nl80211_bss_select_rssi_adjust *adj_param;



		adj_param = nla_data(attr[NL80211_BSS_SELECT_ATTR_RSSI_ADJUST]);

		bss_select->behaviour = NL80211_BSS_SELECT_ATTR_RSSI_ADJUST;

		bss_select->param.adjust.band = adj_param->band;

		bss_select->param.adjust.delta = adj_param->delta;

		if (!is_band_valid(wiphy, bss_select->param.adjust.band))

			return -EINVAL;

	}



	/* user-space did not provide behaviour attribute */

	if (bss_select->behaviour == __NL80211_BSS_SELECT_ATTR_INVALID)

		return -EINVAL;



	if (!(wiphy->bss_select_support & BIT(bss_select->behaviour)))

		return -EINVAL;



	return 0;

}



static int nl80211_parse_random_mac(struct nlattr **attrs,

				    u8 *mac_addr, u8 *mac_addr_mask)

{
@@ -8001,6 +8097,21 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info) 
		return -EOPNOTSUPP;

	}



	if (info->attrs[NL80211_ATTR_BSS_SELECT]) {

		/* bss selection makes no sense if bssid is set */

		if (connect.bssid) {

			kzfree(connkeys);

			return -EINVAL;

		}



		err = parse_bss_select(info->attrs[NL80211_ATTR_BSS_SELECT],

				       wiphy, &connect.bss_select);

		if (err) {

			kzfree(connkeys);

			return err;

		}

	}



	wdev_lock(dev->ieee80211_ptr);

	err = cfg80211_connect(rdev, dev, &connect, connkeys, NULL);

	wdev_unlock(dev->ieee80211_ptr);